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Onoe, Hironori; Ishibashi, Masayuki*; Ozaki, Yusuke; Iwatsuki, Teruki
International Journal of Rock Mechanics and Mining Sciences, 144, p.104737_1 - 104737_14, 2021/08
Times Cited Count：4 Percentile：34.69(Engineering, Geological)In this study, we investigated the methodology of modeling for fractured granite around the drift at a depth of 500 m in the Mizunami Underground Laboratory, Japan as a case study. As a result, we developed the fracture modeling method to estimate not only geological parameters of fractures but also hydraulic parameters based on the reproducibility of trace length distribution of fractures. By applying this modeling method, it was possible to construct a Discrete Fracture Network (DFN) model that can accurately reproduce the statistical characteristics of fractures.
Onoe, Hironori; Yamamoto, Shinya*; Kohashi, Akio; Ozaki, Yusuke; Sakurai, Hideyuki*; Masumoto, Kiyoshi*
JAEA-Research 2018-003, 84 Pages, 2018/06
JAEA-Research-2018-003.pdf:17.44MB
In this study, numerical experiments considered hydrogeological structures, which has high heterogeneity around the Mizunami Underground Research Laboratory and inverse analysis using in-situ data were carried out. The results showed that concentration of hydrogeological structure to be estimated and location of monitoring point is important for application of inverse analysis. Furthermore, it is concluded that inverse analysis using hydraulic response due to pumping test is effective for hydrogeological characterization.
Aoyagi, Kazuhei; Kamemura, Katsumi*; Nago, Makito*; Sugawara, Kentaro*; Matsubara, Makoto*
Proceedings of ITA-AITES World Tunnel Congress 2017 (WTC 2017) (USB Flash Drive), 10 Pages, 2017/06
An in situ stress state is one of the important factors in the design of deep underground facility of high-level radioactive waste disposal repository. This study establishes a practical and effective method for estimating in situ stress state on the basis of the measured convergence during gallery excavation. The convergence was measured in various directions of the loop gallery at 350m depth of the Horonobe Underground Research Laboratory; this allows determination of the stress state corresponding to the rock mass deformation behavior in an approximately 120 m* 200 m area. To estimate in situ stress state around that area, a back analysis method considering the existence of faults and fractures around the gallery was developed. The analyzed results showed a good agreement with the trend of in situ stress state estimated from hydraulic fracturing method.
Onoe, Hironori; Saegusa, Hiromitsu; Takeuchi, Ryuji
Doboku Gakkai Rombunshu, C (Chiken Kogaku) (Internet), 72(1), p.13 - 26, 2016/01
The Japan Atomic Energy Agency is conducting the Mizunami Underground Research Laboratory (URL) project in Mizunami, Gifu, in order to establish scientific and technical basis for geological disposal of high-level radioactive waste. This paper comprehensively describes the result of groundwater flow modeling using data of hydraulic responses and hydrochemical changes due to URL construction. Technical know-how and methodology of hydrogeological monitoring and groundwater flow modeling were presented for characterization of hydraulic heterogeneities in fractured crystalline rock. Furthermore, effectivity of data acquisition of hydrochemical changes in groundwater for validation of result of groundwater flow modeling was indicated.
Chinju, H.*; Nagasaki, Shinya*; Tanaka, Satoru*; Sakamoto, Yoshiaki; Takebe, Shinichi; Ogawa, Hiromichi
Journal of Nuclear Science and Technology, 38(8), p.645 - 654, 2001/08
Times Cited Count：3 Percentile：27.1(Nuclear Science & Technology)no abstracts in English
*; *; *; *
JNC TJ8400 2000-006, 232 Pages, 2000/05
JNC-TJ8400-2000-006.pdf:7.75MB
In this research, simulations with some parameters which characterize ground water flow and the reliability evaluation for the expansion of the calculation method of groundwater flow were carried out by using the radionuclide transport computations in nearfield heterogeneous porous media. Concretely contents are follows: (1)With the series of calculation method for three-dimensional saturated/unsaturated groundwater flow and one-dimensional radionuclide transport. the computational analyses with the parameters used in JNC report in 2000 was carried out and the influence of the different input flux was evaluated. (2)The examination of the application for the different ways of inverse laplace transformation which is used in one-dimensional radionuclide tansport analysis code "MATRICS" was carried out. (3)The examination of the application of multi-element "MATRICS" (m-MATRICS) for radionuclide transport computations in nearfield heterogeneous porous media was carried out. (4)The series of calculation methods from three-dimensional saturated/unsaturated ground water flow simulation code to one-dimensional radionuclide transport simulation code was integrated.
Sawada, Atsushi; Ijiri, Yuji; *; Watari, Shingo
JNC TN8400 99-093, 58 Pages, 1999/11
This paper decribes the results of PA studies considering heterogeneous fracture characteristics, for the purpose of contributing for the performance assessment of the natural barrier system PA in H12 report (The second progress report on research and development for the Geological Disposal of HLW in Japan). In this study, 3-D discrete fracture network mode1 (DFN) and 1-D multiple pathways model is applied for 100m scale of rock block. Although nuclide release rate calculated by DFN are widely distributed among the realizations, it is shown that several tens realizations are enough number to understand the stochastic characteristics of the nuclide release. From the data uncertainty analysis, there are no significant effects for the nuclide retardation in fracture geometry parameters such as fracture radius, density and etc. 1-D multiple pathways model is developed with focusing on the heterogeneity of the transmissivity, which has a large effect to the nuclide retardation effects. The nuclide release rate calculated by using 1-D multiple pathways model approximates to the results of DFN. This result also shows that the relatively large fractures/faults that connects disposal tunnel and downstream faults have an important role for performance assessment in natural barrier system.
Onoe, Hironori; Saegusa, Hiromitsu; Iwasaki, Riyo; Ishibashi, Masayuki; Takeuchi, Ryuji; Hama, Katsuhiro
no journal, ,
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Onoe, Hironori; Yamamoto, Shinya*; Masumoto, Kiyoshi*; Kohashi, Akio; Saegusa, Hiromitsu
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Yamamoto, Shinya*; Honda, Makoto*; Sakurai, Hideyuki*; Onoe, Hironori; Masumoto, Kiyoshi*
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Ota, Ryosuke*; Mitsuyama, Kazuaki*; Tachi, Yukio; Yotsuji, Kenji*; Sato, Tomofumi*; Sato, Hisao*; Martin, A.*
no journal, ,
The radionuclide migration model representing heterogeneities in distributions of minerals and pores was developed for Grimsel granodiorite. This model was applied to quantify the impact of heterogeneities on radionuclide migration and was validated by comparing with the measured data.
Onoe, Hironori; Murakami, Hiroaki; Ozaki, Yusuke; Watanabe, Yusuke; Takeuchi, Ryuji; Iwatsuki, Teruki
no journal, ,
no abstracts in English
Kimoto, Kazushi*; Okano, Aoi*; Saito, Takayasu*; Sato, Tadanobu*; Matsui, Hiroya
no journal, ,
This study investigates the propagation characteristics of high frequency surface wave in a granite block by ultrasonic measurements. To this end, a surface wave field excited by a line-focus transducer is scanned finely over a rectangular aperture with a laser Doppler vibrometer. From the measured waveforms, the spatial distribution of Fourier phase is reconstructed, and the structure of the wave front system is investigated. Due to the heterogeneity of the granite, the wave fronts fluctuate spatially at a rate dependent on the ultrasonic frequency. The intensity of the fluctuation is then quantified as a local wavenumber vector. It was found as a result that the granite sample can be characterized by a random wave number whose probability density is frequency dependent, asymmetric and non-Gaussian having a finite support.
Takahashi, Yuta
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no abstracts in English
Onoe, Hironori*; Saegusa, Hiromitsu*; Tanaka, Tatsuya*; Ishida, Keisuke*; Fujisaki, Kiyoshi*; Sawada, Atsushi
no journal, ,
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Hane, Koji*; Onoe, Hironori*; Ishibashi, Masayuki*; Tabei, Kazuto*; Namikawa, Tadashi*; Tagawa, Yoichi*; Saegusa, Hiromitsu*; Ishida, Keisuke*; Fujisaki, Kiyoshi*; Sawada, Atsushi
no journal, ,
no abstracts in English
Murayama, Shota*; Takeda, Masaki; Ono, Hirokazu; Tachi, Yukio
no journal, ,
To evaluate mass transport in a fault zone containing multiple fractures, it is necessary to develop an mass transfer model based on the characteristics of the actual fault zone, and to conduct an in-situ tracer test. It is important to obtain information on the transport path and parameters through the tracer test. This paper presents the results of the tracer test conducted in a fault zone in the 350m research drift of Horonobe URL. The spatial distributions of the fractures and transport paths were evaluated based on the observation of the core sample collected after the tracer test and the tracer concentration analysis on the fracture surface. Furthermore, the transport model was applied and validated thorough the interpretation of the test results.
Onoe, Hironori*; Ishibashi, Masayuki*; Esaki, Taichi*; Tagawa, Yoichi*; Tabei, Kazuto*; Namikawa, Tadashi*; Hane, Koji*; Saegusa, Hiromitsu*; Ishida, Keisuke*; Sawada, Atsushi
no journal, ,
no abstracts in English
